A police officer has been killed and another wounded in a shooting in western Pennsylvania.

The officers were responding to a domestic disturbance call in Canonsburg, 20 miles south-west of Pittsburgh, at about 3.15am on Thursday.

State police trooper Melinda Bondarenka said the officers were “ambushed upon their arrival” at the scene and immediately shot. They were taken to hospital, where Canonsburg officer Scott Leslie Bashioum, age 52, died. The other officer, who has not been identified, is in fair condition, according to a hospital spokesman.

Voters in three states voted to legalize the use of marijuana for recreational purposes on Tuesday, and four more states voted to allow marijuana use for medicinal purposes, the largest mass liberalization of pot laws in the nation’s history.

California, Nevada and Massachusetts join four other states — Oregon, Washington, Alaska and Colorado — to legalize marijuana for recreational use. A similar ballot measure in Maine is leading by just 4,000 votes, less than 1 percent of all votes cast, with most precincts reporting, though the Associated Press has not called that contest.

Californians voted Tuesday to pass Proposition 63, a sweeping gun control measure that will bolster the state’s already substantial restrictions on firearms and ammunition.

The ballot initiative, spearheaded by California Lt. Gov. Gavin Newsom (D), will implement a slew of new gun regulations intended to help prevent mass shootings. The measure bans possession of large-capacity magazines, mandates background checks and permits for ammunition purchases, requires individuals and businesses to report lost or stolen firearms, and makes all firearm thefts felonies regardless of the value of the weapon. The measure will also set up a process for courts to remove guns from people convicted of certain crimes.

Testimony by police officers in the Charleston, S.C., trial of former officer Michael Slager contradicted the account he gave immediately after the shooting of a civilian.

Tuesday was the third day of testimony in the case. Slager faces a murder charge in the death of Walter Scott, who was shot after he fled from Slager after a traffic stop on Apr. 4, 2015. Slager first attempted to subdue Scott with a Taser before any bullets were fired. Cellphone video footage taken by a passerby indicates Scott was shot five times in the back as he ran away from Slager.

Janet Reno, the first woman to serve as U.S. attorney general and the epicenter of several political storms during the Clinton administration, including the seizure of Elian Gonzalez, died early Monday. She was 78.

Reno died from complications of Parkinson's disease, her goddaughter Gabrielle D'Alemberte said. D'Alemberte said Reno spent her final days at home in Miami surrounded by family and friends.